Finance & Investment
Mortgage Calculator
Mortgage: it amortises the loan with the reducing-balance formula E = P·r·(1+r)^n / ((1+r)^n − 1) and splits each payment into interest and principal. Worked through below with real figures, and the calculator repeats the working on your own inputs — free, on-device, instant.
Mortgage Calculator is a browser-based way to work out the monthly repayment and total cost of a loan. Feed it your home price, down payment, annual interest rate and loan term and it computes the monthly payment, total interest and a full breakdown on the spot, keeping your data local.
About this calculator
Mortgage is easiest to get wrong in the setup, not the arithmetic. It amortises the loan with the reducing-balance formula E = P·r·(1+r)^n / ((1+r)^n − 1) and splits each payment into interest and principal. It matters any time money changes value over time — savings, loans, investments, prices and pay all reduce to these relationships. The worked example on this page (A 250,000 mortgage at 6.5% over 30 years (360 months): payment = 1,580.17/month .) shows the full substitution; the calculator above runs the same working on your own numbers, in your browser, with nothing uploaded.
How to use
- Enter the home price.
- Enter your down payment.
- Enter the annual interest rate.
- Press Calculate to see the loan amount, payment, and LTV.
Why use Mortgage Calculator
Fast
Calculations run in your browser. No round trip to a server.
Private
Your inputs never leave your device. Nothing is uploaded.
Free
No signup, no paywall, no ads-in-results, no watermarks.
Educational
Uses simplified financial formulas for educational estimates. Results may not include fees, taxes, insurance, lender rules, penalties, or credit decisions.
Mobile-ready
Optimised for phones, tablets, and desktops alike.
Transparent
Clear about the method used and its limits, with disclaimers where they matter.
Common uses
Use it when comparing home-loan offers
Use it for prepayment and part-payment planning
Use it when planning a home-loan EMI
Use it when applying for a mortgage
Use it when checking affordability before buying
Use it for sizing a down payment
Technical notes
Mortgage Calculator amortises the loan with the reducing-balance formula E = P·r·(1+r)^n / ((1+r)^n − 1) and splits each payment into interest and principal.
A real mortgage adds property taxes, insurance and possible PMI on top of the principal and interest shown.
The tool works offline once loaded, since every computation is client-side.
FAQ
How is the loan amount worked out?
The loan equals the home price minus your down payment. The monthly payment is then calculated on that loan over the term you choose.
What is loan-to-value (LTV)?
LTV is the loan as a percentage of the home price. A larger down payment lowers LTV, which can mean better rates and no mortgage insurance.
Does this include taxes and insurance?
No. It shows principal and interest only. Property tax, home insurance, HOA, and PMI are additional and vary by location and lender.
Does the Mortgage Calculator send my data to a server?
No. The Mortgage Calculator runs entirely in your browser — your inputs never leave your device, and nothing is uploaded or stored.
Worked example
A 250,000 mortgage at 6.5% over 30 years (360 months): payment = 1,580.17/month.